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<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
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    <title>Document</title>
    <script>
        //把cc替换成ss
        const array1 = ['aa','bb','cc','dd','ee','ff'];
        
        // console.log(array1.fill('ss',2,3))
        
        console.log(array1.splice(2,0,'ss','yy','zz'))
        console.log(array1)

        
    </script>
</head>
<body>
    
</body>
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